Date: Sat, 07 Apr 2007 08:34:09 +0100 From: Matthew Seaman <m.seaman@infracaninophile.co.uk> To: "R. B. Riddick" <arne_woerner@yahoo.com> Cc: freebsd-fs@freebsd.org, Mike Wolman <mike@nux.co.uk>, freebsd-questions@freebsd.org Subject: Re: some thoughts about gmirror Message-ID: <46174971.9080809@infracaninophile.co.uk> In-Reply-To: <219395.34786.qm@web30302.mail.mud.yahoo.com> References: <219395.34786.qm@web30302.mail.mud.yahoo.com>
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R. B. Riddick wrote:
> Sounds like rsync can already do that (I am not sure right now, if rsyn=
c can
> find updated areas within a large file, or if it just copies the while =
updated
> file even if it is a large one)...
rsync will find an updated area within a big file. The algorithm is to
divide any such file into 100kB[*] chunks, calculate checksums of each of=
those chunks and only transfer the chunks where the checksum differs
between source and destination. More detail here:
http://samba.org/rsync/how-rsync-works.html
http://rsync.samba.org/tech_report/tech_report.html
Cheers,
Matthew
[*] For some value of 100kB.
--=20
Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard
Flat 3
PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate
Kent, CT11 9PW
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